this may help - 
sreten.
Lets say for your arm vertical mass = 3.5g and lateral = 35g.
With the Ortofon 2.5g you have 6g total vertical, 37.5 total lateral.
25 cu = ~ 13Hz vertical and ~ 5Hz lateral.
Note adding the 2.5g weight would increase lateral mass much
more because your counterwieght would need to be 50% heavier.
Making the counterweight lighter and moving it out further is
one way of increasing vertical mass whilst reducing lateral mass.
sreten.Lets say for your arm vertical mass = 3.5g and lateral = 35g.
With the Ortofon 2.5g you have 6g total vertical, 37.5 total lateral.
25 cu = ~ 13Hz vertical and ~ 5Hz lateral.
Note adding the 2.5g weight would increase lateral mass much
more because your counterwieght would need to be 50% heavier.
Making the counterweight lighter and moving it out further is
one way of increasing vertical mass whilst reducing lateral mass.
Attachments
Jesus!!! What have I got myself into....
I had no idea that it was so many parameters to take concern to.
I´m afraid I start loosing the grip just as I thought that things turned out to be clear
It´s too much science for me to handle, maybe I shouldn´t have taken up the thread
However, I´m sure it all works out in the end.....
Now I have to continue eating my ravioli, that´s basic stuff
I had no idea that it was so many parameters to take concern to.
I´m afraid I start loosing the grip just as I thought that things turned out to be clear
It´s too much science for me to handle, maybe I shouldn´t have taken up the thread
However, I´m sure it all works out in the end.....
Now I have to continue eating my ravioli, that´s basic stuff
Sreten : after reading your latest posts with my stomach full of ravioli and beer, I found it resonable to go for 'as light as possible'. It seems that the Resonance Frequency will end up under the audioable area:
Your attached Resonance Frequency-tabel probably proves that, but I don´t know how to read it.
So I´ll try with the Ortofon OM 30 Super, it´s a cheap p.u & I must start somewhere. Better to test it all out first and upgrade later if it´s nessesary. And it´s certainly better than my old 'K9', but I wounder about this:
How do I remove the weight, is there a big risk to damage the p.u when doing it?
Best regards
Your attached Resonance Frequency-tabel probably proves that, but I don´t know how to read it.
So I´ll try with the Ortofon OM 30 Super, it´s a cheap p.u & I must start somewhere. Better to test it all out first and upgrade later if it´s nessesary. And it´s certainly better than my old 'K9', but I wounder about this:
How do I remove the weight, is there a big risk to damage the p.u when doing it?
Best regards
the axis are a little confusing,
left is from 6Cu up to 40cu,
the bottom is from 4g to 40 g.
The weight in the cartridge is the shiny bit you can see,
it simply falls out.
The compliance issue is fairly straight forward for the OM30.
If you make a lightweight arm, a lightweight slide and
use a spaced counterweight you'll be absolutely fine.
How you make a lightweight slide may take some thought.
But now you are aware that the mass of all the moving parts
are relevent laterally your unlikely to use say a too heavy slide,
which you may have done before, the relative mass of all the
parts will be obvious, if the slide weight is similar to the the
counterweight it will be fine, a lot more, not so good.
With a spaced counterweight the vertical mass should
fall out to be a reasonable value for the OM30.
sreten.
left is from 6Cu up to 40cu,
the bottom is from 4g to 40 g.
The weight in the cartridge is the shiny bit you can see,
it simply falls out.
The compliance issue is fairly straight forward for the OM30.
If you make a lightweight arm, a lightweight slide and
use a spaced counterweight you'll be absolutely fine.
How you make a lightweight slide may take some thought.
But now you are aware that the mass of all the moving parts
are relevent laterally your unlikely to use say a too heavy slide,
which you may have done before, the relative mass of all the
parts will be obvious, if the slide weight is similar to the the
counterweight it will be fine, a lot more, not so good.
With a spaced counterweight the vertical mass should
fall out to be a reasonable value for the OM30.
sreten.Attachments
Regarding the graph
And assume a cartridge mass of 5g.
some Cu's - 10, 20, 30
some arm effective masses 5, 15, 25
which give total effective mass 10, 20, 30
You look where they intersect and at the nearest lines.
10 cu - 10g = ~ 16 Hz
10 cu - 20g = ~ 11 Hz
10 cu - 30g = ~ 9 Hz
20 cu - 10g = ~ 11 Hz
20 cu - 20g = ~ 8 Hz
20 cu - 30g = ~ 6.5 Hz
30 cu - 10g = ~ 9 Hz
30 cu - 20g = ~ 6.5 Hz
30 cu - 30g = ~ 5.3 Hz
On a turntable like your Thorens target is 10Hz.
sreten.
And assume a cartridge mass of 5g.
some Cu's - 10, 20, 30
some arm effective masses 5, 15, 25
which give total effective mass 10, 20, 30
You look where they intersect and at the nearest lines.
10 cu - 10g = ~ 16 Hz
10 cu - 20g = ~ 11 Hz
10 cu - 30g = ~ 9 Hz
20 cu - 10g = ~ 11 Hz
20 cu - 20g = ~ 8 Hz
20 cu - 30g = ~ 6.5 Hz
30 cu - 10g = ~ 9 Hz
30 cu - 20g = ~ 6.5 Hz
30 cu - 30g = ~ 5.3 Hz
On a turntable like your Thorens target is 10Hz.
sreten.
Thanks for filling the blaks about the graph, but why should 10Hz be good for my Thorens?
How do I know what will be right for my new table? That will be a non-suspention-table, if that makes any differances (it probably does, everything seems to matter).
Are there any place on the net where I can learn more about stuff like this, could be fun to know the theory behind the result.
How do I know what will be right for my new table? That will be a non-suspention-table, if that makes any differances (it probably does, everything seems to matter).
Are there any place on the net where I can learn more about stuff like this, could be fun to know the theory behind the result.
Basically for your solid turntable and type of arm its a compromise.
All records are eccentric to some degree. At 33.3 rpm this means
the arm has to move side to side at ~ 2Hz, a lateral resonance
of 2Hz is not good , 3hz is not good for 45rpm records.
Whether the arm would actually work would depend on the
amount of damping in the system, but its obvious a higher
lateral resonant requency is a much better idea.
Record warps fortunately are in the vertical direction but again
nearly all records are not perfectly flat, so 2 Hz and 3Hz again.
Bad warps or ripples - you tell me - but obviously quite a bit
higher frequencies are generated, generally presumed to be
up to 6Hz.
Good turntable suspension design will also try to keep all
frequency modes below 6 Hz and its genarally accepted
3Hz to 4Hz is a good suspension frequency.
This means the lowest arm frequency generally useable is
~ 8 Hz. But 10Hz is better.
However the higher the frequency the lower the compliance
and the poorer the low frequency tracking, so basically you
don't want to raise the frequency too much.
8Hz to 13 Hz is a good range but the nearer 10Hz the better.
Note that DJ's typically use nearer 15Hz, with a coin on the headshell.
For your arm its a compromise between mass i.e. structural
integrity and the frequency of the lateral resonance. If the
vertical resonance is too high you start to get a bass boost
(but only for out of phase bass so not really an issue)
IMO the compromise for a medium compliance low mass MM
and a higher mass low compliance MC would roughly be the
same, with a stronger build for the MC the lateral frequency
would end up very similar.
My target for your arm would be 4.5Hz to 5Hz = 55g to 40g total mass,
if the total mass turns out lower great, up to to say 75g fine also.
sreten.
All records are eccentric to some degree. At 33.3 rpm this means
the arm has to move side to side at ~ 2Hz, a lateral resonance
of 2Hz is not good , 3hz is not good for 45rpm records.
Whether the arm would actually work would depend on the
amount of damping in the system, but its obvious a higher
lateral resonant requency is a much better idea.
Record warps fortunately are in the vertical direction but again
nearly all records are not perfectly flat, so 2 Hz and 3Hz again.
Bad warps or ripples - you tell me - but obviously quite a bit
higher frequencies are generated, generally presumed to be
up to 6Hz.
Good turntable suspension design will also try to keep all
frequency modes below 6 Hz and its genarally accepted
3Hz to 4Hz is a good suspension frequency.
This means the lowest arm frequency generally useable is
~ 8 Hz. But 10Hz is better.
However the higher the frequency the lower the compliance
and the poorer the low frequency tracking, so basically you
don't want to raise the frequency too much.
8Hz to 13 Hz is a good range but the nearer 10Hz the better.
Note that DJ's typically use nearer 15Hz, with a coin on the headshell
.For your arm its a compromise between mass i.e. structural
integrity and the frequency of the lateral resonance. If the
vertical resonance is too high you start to get a bass boost
(but only for out of phase bass so not really an issue)
IMO the compromise for a medium compliance low mass MM
and a higher mass low compliance MC would roughly be the
same, with a stronger build for the MC the lateral frequency
would end up very similar.
My target for your arm would be 4.5Hz to 5Hz = 55g to 40g total mass,
if the total mass turns out lower great, up to to say 75g fine also.
sreten.
and we are glad to have 
45 back here.Some brainfade in my last post.
The eccentric frequency is ~ 0.5Hz for 33.3 rpm and 0.75Hz for 45
rpm not 2Hz and 3hz as I erroneously stated, what was I thinking ?
The 2Hz to 3hz region is were most record ripples warps reside.
A good "test" for an air bearing arm is taking the centre
out of a 45 rpm single and deliberately placing it eccentric.
sreten.
The eccentric frequency is ~ 0.5Hz for 33.3 rpm and 0.75Hz for 45
rpm not 2Hz and 3hz as I erroneously stated, what was I thinking ?
The 2Hz to 3hz region is were most record ripples warps reside.
A good "test" for an air bearing arm is taking the centre
out of a 45 rpm single and deliberately placing it eccentric.
sreten.sreten,
well, as you corrected yoursellf already, lateral excitation happens at 0.55Hz@33rpm (and 1.32Hz@78rpm ... I'd say that a lower lateral resoncance at >3Hz is probably far enough apart from that to prevent oscillation or keep it within bearable limits (i always assume that the cartridge's cantilever supsension has a considably high amount of damping -- the suspension consists of rubber after all with a decent movement-2-friction-heat conversion .... and all possible hysteresis and relaxation effects take place too )
Passive linear trackers and lightweight supension TTs don't cooperrate, agreed. But give your air-suspended TT plinth some weight, maybe 100kg?, and make the air springs reasonably low-damped and level the sucker and you may find you like the sonics very much ....
Hmm, i em no ´neeetif speeka, do you mean by "take issue with" that you disagree?
My experience with low lateral tonearm resonance and low compliance: the cartridge may mistrack or not, in any case it doesn't loose track i.e.it jumps back into the same groove.
No question that an old, worn, weak-of-age MC cartridge which maybe manaages to track 60µm (or only 50µm?) on the ortofon 0002 will mistrack at the 1812 cannons.
But atleast the music goes on (rhythmically) uninterupted, due to the high lateral inertia of the tonearm. Yeah, i know, a dirty defintion of tracking ability
And a cartridge which is at its tracking limit in a usual pivoted arm marches around the edgy corners with stunning ease in a laterally low resonating linear tracker. I just tried that out.
But, admitted, i did not measure THD.
With your LT test (excentric 45rpm) i would not be happy (circus artistry ) : the linear tracker has much more lateral effective mass compared to a pivoted arm and the poor cartridge has to suffer. You do that with your own Koetsu Onyx Platinum, you hear me?
Volker Kühn from audioplan (he now runs BlackForestAudio and distributes Fertin speakers among others) used to demonstrate the Souther arm (now marketed by clearaudio): the arm did that test fine but the rail had (and still has)to be cleaned 3 times a record side. ROTFLMAO , excentric test made but real life test flunked .
DTopic, you provided a lot of useful info here, goes straight into my keep folder, THANXALOT!
Plysch,
thanx for the compliment.
My LT-2 (the project has suuuuch a long beard, i do not even call it LT-2 any more) evolved a bit from what your see on my site.
It is still in design state, a functional prototype is coming the next few months and i expect to have a preproduction prototype coming December. no idea if i manage that, my job i eating me and my head always feels like broken.
But LT-2 will have some more freatures than just a framework tonearm wand. I will have a lateral force compensation (call that an antiskate substitution mechanism -- i want to have my lateral bias defined as i like it, no as the tomearm prescribes), different wands for different cartridges, 2 minute cartridge exchange time, adjusting and measuring tools for any ****ing geometry parameter (thus providing 100% parameter reproducabliity) ... oh yes and i will have phono connectors without any magnetic components, just solid/massive 99.99% silver contacts and PEEK insulators. One of those connectors will be fully RCA/Cinch compatible (plug AND jack!), the other one will be my own thing, tinytiny, untra-leightweight and connecting the
LT-2 slider to the phono interconnect (which also will use silver wire, single-strand of course). I just hated the thought to loose in the connector what my tonearm just had sonically achieved. And 75µm single strand wire does not stand heavy connectors -- just let the plug slip out of your hand and the wires are ripped off.
All for now, gotta work
sreten said:
well, as you corrected yoursellf already, lateral excitation happens at 0.55Hz@33rpm (and 1.32Hz@78rpm
... I'd say that a lower lateral resoncance at >3Hz is probably far enough apart from that to prevent oscillation or keep it within bearable limits (i always assume that the cartridge's cantilever supsension has a considably high amount of damping -- the suspension consists of rubber after all with a decent movement-2-friction-heat conversion .... and all possible hysteresis and relaxation effects take place too ) Passive linear trackers and lightweight supension TTs don't cooperrate, agreed. But give your air-suspended TT plinth some weight, maybe 100kg?, and make the air springs reasonably low-damped and level the sucker and you may find you like the sonics very much ....
Hmm, i em no ´neeetif speeka, do you mean by "take issue with" that you disagree?
My experience with low lateral tonearm resonance and low compliance: the cartridge may mistrack or not, in any case it doesn't loose track i.e.it jumps back into the same groove.
No question that an old, worn, weak-of-age MC cartridge which maybe manaages to track 60µm (or only 50µm?) on the ortofon 0002 will mistrack at the 1812 cannons.
But atleast the music goes on (rhythmically) uninterupted, due to the high lateral inertia of the tonearm. Yeah, i know, a dirty defintion of tracking ability
And a cartridge which is at its tracking limit in a usual pivoted arm marches around the edgy corners with stunning ease in a laterally low resonating linear tracker. I just tried that out.
But, admitted, i did not measure THD.
With your LT test (excentric 45rpm) i would not be happy (circus artistry
) : the linear tracker has much more lateral effective mass compared to a pivoted arm and the poor cartridge has to suffer. You do that with your own Koetsu Onyx Platinum, you hear me? Volker Kühn from audioplan (he now runs BlackForestAudio and distributes Fertin speakers among others) used to demonstrate the Souther arm (now marketed by clearaudio): the arm did that test fine but the rail had (and still has
)to be cleaned 3 times a record side. ROTFLMAO , excentric test made but real life test flunked .DTopic, you provided a lot of useful info here, goes straight into my keep folder, THANXALOT!
Plysch,
thanx for the compliment.
My LT-2 (the project has suuuuch a long beard, i do not even call it LT-2 any more) evolved a bit from what your see on my site.
It is still in design state, a functional prototype is coming the next few months and i expect to have a preproduction prototype coming December. no idea if i manage that, my job i eating me and my head always feels like broken.
But LT-2 will have some more freatures than just a framework tonearm wand. I will have a lateral force compensation (call that an antiskate substitution mechanism -- i want to have my lateral bias defined as i like it, no as the tomearm prescribes), different wands for different cartridges, 2 minute cartridge exchange time, adjusting and measuring tools for any ****ing geometry parameter (thus providing 100% parameter reproducabliity) ... oh yes and i will have phono connectors without any magnetic components, just solid/massive 99.99% silver contacts and PEEK insulators. One of those connectors will be fully RCA/Cinch compatible (plug AND jack!), the other one will be my own thing, tinytiny, untra-leightweight and connecting the
LT-2 slider to the phono interconnect (which also will use silver wire, single-strand of course). I just hated the thought to loose in the connector what my tonearm just had sonically achieved. And 75µm single strand wire does not stand heavy connectors -- just let the plug slip out of your hand and the wires are ripped off.
All for now, gotta work
dice45 said:
Hmm, i em no ´neeetif speeka, do you mean by "take issue with" that you disagree?
My experience with low lateral tonearm resonance and low compliance: the cartridge may mistrack or not, in any case it doesn't loose track i.e.it jumps back into the same groove.
No question that an old, worn, weak-of-age MC cartridge which maybe manaages to track 60µm (or only 50µm?) on the ortofon 0002 will mistrack at the 1812 cannons.
But atleast the music goes on (rhythmically) uninterupted, due to the high lateral inertia of the tonearm. Yeah, i know, a dirty defintion of tracking ability
And a cartridge which is at its tracking limit in a usual pivoted arm marches around the edgy corners with stunning ease in a laterally low resonating linear tracker. I just tried that out.
But, admitted, i did not measure THD.
With your LT test (excentric 45rpm) i would not be happy (circus artistry
Volker Kühn from audioplan (he now runs BlackForestAudio and distributes Fertin speakers among others) used to demonstrate the Souther arm (now marketed by clearaudio): the arm did that test fine but the rail had (and still has
DTopic, you provided a lot of useful info here, goes straight into my keep folder, THANXALOT!
By "take issue with" I meant prepared to argue the point.
By "tracking capability" I didn't realise you were referring to
nice mistracking characteristics, I took its meaning literally.
In the literal context the OM30 will be rather good.
The offset 45 comment was a little flippant. But an old LP
with a filed hole, say 2mm could be useful for checking the
arm at various points across the record.
sreten.sreten said:
sreten,
i was often always grilled by rather scholastic, measuring-oriented guys with my preference for passive linear trackers and in particular in combination with MC cartridges. No question, probably nothing beats the proper tracking of Shure V15V properly mounted into an SME3009/III.
And i doubt that high-compliant cartridges will feel fine in a passive linear tracker. BTW, my goal with LT-2 is to male a V15V atleast work in my LT-2. But i don't expect it to sing and swing and meake my feet tap and my body shake
.... (i dont expect the V15V make me respond that way in any arm but in a passive linear tracker i expect it to sound particularly awful)IMO the high lateral inertia in combination with disc excentricity ages a phono cartridge way before its time has come. Not to speak of the precious records. If one wants to be happy with a linear tracker on the long run, IMO it is vital to have some way to compensate excentricity of the canter hole in order make the arm's slider move spindlewards continuously and not inwards/outwards oscillating. The TT i have on my back-burner has such a device: the platter spindle pin is only 3mm dia and on excentic records the excentricity is marked by an open pencil-drawn circle having exactly the dia of the vacuum nozzle -- i have a jig for measuring and marking the excentricity of the groove pattern in repect to the center hole.
This is my 1st measure to make the linear tracker move uniformly. My 2nd measure is the lateral force compensation i mentioned above; this has a nice side effect: i can make sure the inner groove is under slightly more pressure than the outer one. I have described the sonic consequences of skating over-compensation in earlier posts.
Now with a passive linear tracker w/o lateral force compensation we always have plenty of skating over-compensation .. and i for my part do not want to have that, sonically (sounding like
).I want to do the whole job right if i have to do it.
Plysch,
i agree with sreten, the Ortofon OM30 indeed is a fine cartridge.
Please look for my earlier posts: how to glue an MM cartridge's cantilever plug-in into the cartridge's body.
I did it often with Ortofon OMB 5 and OMB 10. Makes a very nice improvement, sonically, and with those Ortofons it is comparatively easy to do. The plug-in costs about 70% of the complete cartridge but the cartridge is budget anyway so why not "pay" for the improvement by cancelling the cartridge body's re-usabliity once the stylus is down.
OK, Dice45, I´ll try to do the glueing of the cantilever into the body, it´ll be interesting to see (hear) if there is any improvment by doing that (I don´t doubt it is but you got to test your ears).
I must thank you & Sreten for an interesting thread, I´ve learned a lot by this and hoping to be able to use it in real life
Good Night.....
I must thank you & Sreten for an interesting thread, I´ve learned a lot by this and hoping to be able to use it in real life
Good Night.....
Hi,
Not sure what you're talking about here but IMO at the speed a record is spinning and assuming lateral movement is not impeded by anything other than the arms' mass I fail to see how:
a) It would wear out a cartridge. Its cantilever doesn't flex laterally unless you have an extremely severe problem causing all sorts of other havoc anyway. In short it won't stay in the groove that way for long.
b) How on earth it can be compensated for as this drag will vary with the degree of excentricity of a record...
Come to think of it, in my entire collection I can't point to a single one being excentric enough to be visible to the naked eye anyway.
c) With a classic pivoted design the problem may well be worse as the excentricity will likely trigger a series of effects, tail wagging do style.
Cartridges such as the Shures being optimized for trackability inevitably lose out on a raft of other parameters.
As these are highly compliant they lose so much inner detail burried in those precious grooves that they're only just O.K. for casual listening.
Given that, I can't be bothered to put them in a LT tonearm design where it will likely be much overdamped no matter what.
Cheers,
Not sure what you're talking about here but IMO at the speed a record is spinning and assuming lateral movement is not impeded by anything other than the arms' mass I fail to see how:
a) It would wear out a cartridge. Its cantilever doesn't flex laterally unless you have an extremely severe problem causing all sorts of other havoc anyway. In short it won't stay in the groove that way for long.
b) How on earth it can be compensated for as this drag will vary with the degree of excentricity of a record...
Come to think of it, in my entire collection I can't point to a single one being excentric enough to be visible to the naked eye anyway.
c) With a classic pivoted design the problem may well be worse as the excentricity will likely trigger a series of effects, tail wagging do style.
Cartridges such as the Shures being optimized for trackability inevitably lose out on a raft of other parameters.
As these are highly compliant they lose so much inner detail burried in those precious grooves that they're only just O.K. for casual listening.
Given that, I can't be bothered to put them in a LT tonearm design where it will likely be much overdamped no matter what.
Cheers,
All,
i'd just like to mention a remark Wally Malewicz made to me.
He told me that he measured lateral forces on pivoted and passive linear tracking arms. He measured it as percentage of the tracking force, using his WallySkater.
He reported that most passive linear trackers have more than 3 times the lateral force of a pivoted arm with Anitskating adjusted to zero.
And .... Frank ....
you thought i would enter a discussion with you, didn't you?
i'd just like to mention a remark Wally Malewicz made to me.
He told me that he measured lateral forces on pivoted and passive linear tracking arms. He measured it as percentage of the tracking force, using his WallySkater.
He reported that most passive linear trackers have more than 3 times the lateral force of a pivoted arm with Anitskating adjusted to zero.
And .... Frank ....
you thought i would enter a discussion with you, didn't you?
dice45 said:
Which is exactly what you'd expect isn't it ?
Lateral force on a cartridge being related to lateral effective mass.
I'd expect a similar difference between high and low mass
pivoted arms, its the extra dynamic force needed that reduces
the resonant frequency for high mass pivoted arms.
Its quite easy to show the deflection angle of a stylus for an
eccentric record is inversely related to the lateral resonant
frequency.
And identical for different mass / compliance combinations as
long as the resonant frequency is the same.
(ignoring friction/stiction)
sreten.fdegrove said:Come to think of it, in my entire collection I can't point to a single one being excentric enough to be visible to the naked eye anyway.
Cheers,
I checked the record sitting on my turntable, budget blues label.
Its quite blatantly eccentric ~ 1mm.
So I'd tried another, CBS, much better and not
noticeable unless you look hard but still there.
So on went a third, here you couldn't see eccentricity as
some minor warp movement made it impossible to judge,
though it did appear to move laterally over the warp.
sreten.
Sreten
and the resonance Q is the same
BTW, i have one of those fancy side force checkers which are meant to replace a cartridge in the headshell and which measure and display lateral stylus force on a small analog instrument at the front. A nice help to check if the lateral force i applied via my LFCM is too big or pointing in the wrong direction (equivalent to antiskating over-compensation). No question, the LFCM only can deliver a constant force, an average lateral force compensation.
All,
about 1/3 of my record collection has an excentric center hole in respect to the groove pattern and considering the fact that most of them are unobtainable, original 1st/2nd pressings with otherwise VG+++ to pristine groove groove wear condition, i cannot even dream of being able to replace it with a comparable copy, after all i collect records since i left school.
And as we are on excentricity, we cannot even rely on the vector of excentricity having the same length and direction for both sides of a given record, quite the contrary. Excentricity of the groove pattern in respect to the center hole can be considerably different for each side of a given record (probably caused by too much backlash in the hinge of a record press and by the fact that the centerhole either is punched afterwards or is part of one half of the record press).
Geometric imperfections on vinyl records are simply an environment condition. Like record warp, pressing bubbles, excentricity, groove2groove Xtalk etc. . Something to be accepted as real life. Not something to be argued with.
Now if i find an easy way to reduce excentricity amplitude to 1 or 2 groove widths, why shouldn't i do it? Centered record sides reward me with a rock-solid imaging and better rhythmic stability.
and the resonance Q is the same
BTW, i have one of those fancy side force checkers which are meant to replace a cartridge in the headshell and which measure and display lateral stylus force on a small analog instrument at the front. A nice help to check if the lateral force i applied via my LFCM is too big or pointing in the wrong direction (equivalent to antiskating over-compensation). No question, the LFCM only can deliver a constant force, an average lateral force compensation.
All,
about 1/3 of my record collection has an excentric center hole in respect to the groove pattern and considering the fact that most of them are unobtainable, original 1st/2nd pressings with otherwise VG+++ to pristine groove groove wear condition, i cannot even dream of being able to replace it with a comparable copy, after all i collect records since i left school.
And as we are on excentricity, we cannot even rely on the vector of excentricity having the same length and direction for both sides of a given record, quite the contrary. Excentricity of the groove pattern in respect to the center hole can be considerably different for each side of a given record (probably caused by too much backlash in the hinge of a record press and by the fact that the centerhole either is punched afterwards or is part of one half of the record press).
Geometric imperfections on vinyl records are simply an environment condition. Like record warp, pressing bubbles, excentricity, groove2groove Xtalk etc. . Something to be accepted as real life. Not something to be argued with.
Now if i find an easy way to reduce excentricity amplitude to 1 or 2 groove widths, why shouldn't i do it? Centered record sides reward me with a rock-solid imaging and better rhythmic stability.
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